Purified water is used in many applications, including the chemical, power, medical and pharmaceutical industries, as well as for human consumption. Typically, prior to use, water is treated to reduce the level of contaminants to acceptable limits. Treatment techniques include physical processes such as filtration, sedimentation, and distillation; biological processes such as slow sand filters or activated sludge; chemical processes such as flocculation and chlorination; and the use of electromagnetic radiation such as ultraviolet light.
Physical filtration systems are used to separate solids from fluids by interposing a medium (e.g., a mesh or screen) through which only the fluid can pass. Undesirable particles larger than the openings in the mesh or screen are retained while the fluid is purified. In water treatment applications, for example, contaminants from wastewater such as storm water runoff, sediment, heavy metals, organic compounds, animal waste, and oil and grease must be sufficiently removed prior to reuse. Water purification plants and water purification systems often make use of numerous water filtration units for purification. It would be desirable to provide improved filtering units to reduce the expense and complexity of such purification systems.